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Kinetic Monte Carlo Simulation of PdZn Alloying and Density Functional Study of PdZn Surface Reactivity towards Water Dissociation
Author(s) -
Cheng Feng,
Chen ZhaoXu
Publication year - 2015
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201500366
Subject(s) - dissociation (chemistry) , alloy , annealing (glass) , monolayer , kinetic monte carlo , materials science , selectivity , kinetics , kinetic energy , thermodynamics , crystallography , chemistry , monte carlo method , chemical physics , nanotechnology , catalysis , metallurgy , organic chemistry , statistics , mathematics , physics , quantum mechanics
Two‐monolayer‐Zn covered Pd(1 1 1) annealed at (low) 500 K exhibits nice CO 2 selectivity for CH 3 OH+H 2 O to CO 2 +H 2 , whereas CO is yielded exclusively when annealed at (high) 650 K. To unravel the reason behind the phenomenon, kinetic Monte Carlo (KMC) simulations were used to study the alloying process. It shows the low temperature annealing produces a multilayer 1:1 PdZn alloy, whereas the high temperature operation results in a Zn‐lean multilayer alloy, not the previously assumed monolayer PdZn alloy on Pd. The geometry and electronic structures of the models derived from KMC simulation agrees with the relevant experiments. The low temperature sample is more active than the high temperature one for H 2 O dissociation, in line with the assumption that H 2 O dissociation controls CO 2 selectivity. It is revealed that triple Zn ensembles which form three‐fold hollow sites account for the activity for H 2 O dissociation.